Here is a quick list and reason for the Devs regarding what we could have in simpleplanes.

1: ability to see who follows you
reason: obvious

2: flares
Reason: would add more..."flare" to combat. If this was implemented then it would allow us to fight air to air more realistically, give slow planes a chance in combat, looks cool.

3: bigger guns
Reason: the standard gun looks like a .50cal. However with a variety of guns we could add new guns like 20mm or 25mm or even 30mm guns. This new guns could have different effects and looks to them.

4: More durability to planes
Reason: it so disappointing to see a small bullet destroy a huge mech or something that should be able to take a huge hit

5:better ai
Reason: they can't drive for crap! They fly ok-ish but driving is like watching a drunk man try to walk a tightrope! It just don't work! Yes I realize this is a tall order but it makes testing for races in the game very difficult